56 lines
1.6 KiB
OCaml
56 lines
1.6 KiB
OCaml
(***********************************************************************)
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(* *)
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(* Objective Caml *)
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(* *)
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(* Xavier Leroy, projet Cristal, INRIA Rocquencourt *)
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(* *)
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(* Copyright 1996 Institut National de Recherche en Informatique et *)
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(* Automatique. Distributed only by permission. *)
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(* *)
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(***********************************************************************)
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(* $Id$ *)
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(* Eratosthene's sieve *)
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(* interval min max = [min; min+1; ...; max-1; max] *)
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let rec interval min max =
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if min > max then [] else min :: interval (min + 1) max
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(* filter p L returns the list of the elements in list L
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that satisfy predicate p *)
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let rec filter p = function
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[] -> []
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(* Application: removing all numbers multiple of n from a list of integers *)
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let remove_multiples_of n =
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filter (fun m -> m mod n <> 0)
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(* The sieve itself *)
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let sieve max =
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let rec filter_again = function
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[] -> []
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| n::r as l ->
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if n*n > max then l else n :: filter_again (remove_multiples_of n r)
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in
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filter_again (interval 2 max)
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let rec do_list f = function
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[] -> ()
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let _ =
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do_list (fun n -> print_int n; print_string " ") (sieve 40000);
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print_newline();
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exit 0
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